21 month old wakes and needs a parent to sleep in his room

My 21 month old son had croup 2 months ago. Since then he wakes up every night between 12 and 5 and demands that my husband sleeps in his room. He has also recently begun to play up going to bed, and it often takes an hour or more for him to go down. We've tried controlled crying in the past, but now he's in a bed, how does this work. We've spoken to people who have put a stair gate on the bedroom door and we are considering this. Anyone tried this, or have any other ideas or advice...please.2 weeks ago we also had another baby so this I understand will be unsettling him also, however its making everything EVEN harder!!

controlled crying works in much the same way in that when he gets out of bed you go to him pick him up don't speak to him put him back in his bed cover him up quick kiss and leave . All in around 30 secs if you can manage it!! We've had a stairgate across dd's bedroom door ever since she went into a bed just before she was 2 she is 3 in april and its still there.